The men stand accused of brutally killing Lathem's younger lover in his luxury condo as part of an alleged plan to carry out "their sexual fantasies of killing others and then themselves."

Trenton James Cornell-Duranleau, 26, was stabbed 70 times to the point where he was left nearly decapitated, according to police.

Prosecutors say the suspects communicated for months about the plan, which an assistant Cook County state's attorney Natosha Toller said included additional victims, though they stand accused of carrying out only one murder.

Lathem is believed by prosecutors to have paid for Warren to travel to the United States before picking him up at Chicago's O'Hare International Airport days before the killing.

Then, on July 26, a day before the killing, Lathem booked a room for Warren near his condo, prosecutors said. Toller said the men struck while Cornell-Duranleau slept.

Toller said Warren watched as Lathem stabbed his own boyfriend with a 6-inch drywall saw knife to the chest and neck.

Cornell-Duranleau is believed to have woken up and fought back. In an effort to stifle his screams, prosecutors say Warren struck Cornell-Duranleau in the head with a lamp before allegedly fetching a knife and joining Lathem in the stabbing.

Instead of killing themselves after the slaying, as prosecutors believe they initially intended, the man fled town. They surrendered to California authorities on Aug. 4 after an eight-day manhunt.